The apparent failure of the probe follows 10 other unresolved cases of bomb blast in Sylhet region since 1997 that left 14 people killed and scores injured.

Initially, 24 people were arrested and put on remand for interrogation on the January 12 blast. Kotwali police transferred the case to the Criminal Investigation Department (CID). But the probe saw no progress.

Moreover, a probe body headed by the superintendent of police, Sylhet, failed to publish a report on the investigation despite repeated extension of time. The report is now gathering dust at the Sylhet police headquarters, said a police official.

Both the CID and Detective Branch of Police (DB) conducted investigations into the incidents of bomb explosion. But in most cases they failed to track down people involved in making the bombs and exploding those.

In 1997, two explosions took place at Sagardighirpar and Ambarkhana in the city. Bangladesh Chhatra League leader Ali Ahmed was killed in the Sagardighirpar blast.

On March 15, 1999, three people were killed as bombs exploded when they were being made at the house of the then ruling Awami League lawmaker Muhibur Rahman Manik at Chhatak upazila headquarters in Sunamganj district.

The legislator, his elder brother, a cousin, a Juba League leader and some others were arrested and charges were pressed against them.

The case was shifted to the Speedy Trial Tribunal, Sylhet, in November 2000. But trial could not start for long due to repeated stay orders by the High Court. However, the trial began recently as the court vacated its stay order.

A blast claimed four lives on September 26, 2001, at the upazila headquarters of Shulla in Sunamganj where AL lawmaker Suranjit Sengupta was addressing a public meeting during the caretaker administration's tenure.

Another blast occurred the same day at a house in the city's Fazilchist area when a public meeting was going on at the nearby Alia Madrassah ground. AL President Sheikh Hasina was the chief guest at the meeting.

Two people engaged in making bombs were killed in the blast.

A few days later, an explosion at a commercial firm in the city's Mirzajangal area left several people injured.

In July last year, a two-storied building was damaged in a bomb explosion at Khadimnagar in the city suburb.

Moreover, a number of bombs and other explosives were recovered at different times from various areas of Sylhet Division.